We have (had ) 11 ducks (mix of WH, Rouen, KC, pekin & mutts) and 5 geese (mutts). A duck was attacked and died on Wednesday night. DH didn't get the door closed well on their run and shed, which is a raised floor Rubbermaid shed attached to 5 cattle panels in an arch that is covered with 1/2" hardware cloth (which goes out 18" onto the ground and is covered by large rocks). DH thought it was a weasel (we lost one to a weasel one early morning about 10 months ago after we let them out). After much searching we found her in the run but the door was open and everyone was outside. Figured human error was the cause. Last night I get home at 10:30 and I see they are acting different. Go out and ALL the ducks have bloody spots on the backs of their necks and heads and one can't stand upright. I begin to wonder if it's the geese causing it, since they aren't injured at all. (Even though the geese have been raised since day olds with these ducks, they are 10 months old right now, and while they haven't been illustrating any mating behavior I know geese can be more aggressive at nesting times.) we get everyone cleaned up as best as we are able in the dark and check out the perimeter and all through the straw in the shed. We find nothing. We put the geese outside the pen and leave the ducks in. We check on them maybe 1/2 dozen times overnight. By morning, the one who couldn't stand well is dead and has been eaten around the spinal cord. So to my questions: could this be the geese that originally did this? Would the ducks cannibalize another duck after the fact? Could something be living in there that would cause this kind of damage that we didn't find? I didn't see the first one who died, but when we had a weasel before it ripped the head off the duck through chicken wire. DH said it was more like wounds this time. This is different. The ducks last night all had wounds from 0.5-1.5" in diameter. They were fine outside all day yesterday (we have an acre or so fenced in with electric wire and chicken wire) and everyone who survived the night is outside now. Help! I don't know how to stop this from happening if I don't know what it is and everyone is so sad here. To lose 2 ducks in 2 nights after 3 years of losing only 1 total is so sad.